The present invention relates to a new and improved method for monitoring a predetrminate or predetrmined yarn quality of a yarn produced by a textile machine, especially a false-twist jet spinning apparatus, and to a new and improved false-twist jet spinning apparatus or performing the inventive method.
In the context of this disclosure, the term "yarn" or equivalent expression, ar used in their broader sense to encompass not only yarns as such, but also threads and other filamentary material.
In the production of yarn, the evenness of the yarn quality at each spinning position or location, as well as the yarn quality of each spinning position or location in comparison to that at the other individual spinning positions or locations, plays an important role.
German Published Patent Application No. 3,517,763 A1, published Nov. 20, 1986, discloses a method and an apparatus for maintaining a predetermined yarn twist to enable checking or controlling the evenness of this yarn quality parameter.
Direct measurement of yarn twist while the spinning process is in progress cannot be achieved. Accordingly, the yarn twist must be estimated with the aid of a yarn diameter measurement. This can be accomplished without contact between the yarn to be measured and the measuring device, i.e. can be measured only indirectly.